To understand the immune response to Francisella tularensis (Ft), and its interaction with immune cells, histological and immunohistochemical analysis of cells and tissues, as well as an analysis of individual immune cell populations and signaling molecules produced, are required. Thus, the purpose of Core C is to provide the means and technological expertise for investigators to analyze immune cells, quantify signalling molecules (cytokines and intracellular signaling molecules), and histologically identify cells and tissues obtained from mice. This includes the use of immunohistochemical techniques to localize and identify antigens on the surface of, and inside immune cells. This Core facilitv will be composed of three primary components: (1) a Flow Cvtometrv service, (2) a Bio-Plex Multiplex Array (BMA) Protein Detection service. and (3) a Histochemistry/lmmunohistochemistry service. All three services are currently available, and being provided to P01 investigators on all 3 currently funded subprojects. In regard to the current proposal, Core C will continue to provide the above services to P01 investigators on all proposed subprojects. The function of the three Immunology Core components is indicated in more detail below: 1. Flow Cytometry Service: This component will provide investigators access to flow cytometry analysis and cell sorting for the purpose of analyzing individual immune cell populations, including surface marker expression and intracellular cytokine production. Specific functions will include: flow cytometer operation, investigator training, equipment maintainance, ordering of reagents and supplies; 2. BMA Protein Detection Service: This component wi utilize an established BMA technology sold by BioRad to quantitate secreted cytokines and intracellular signalling molecules utilizing a Bio-Plex 200 instrument dedicated to this purpose. Specific functions wil| include: acquiring reagents and kits, performing assays, performing analysis of samples, assisting in data/assay interpretation when appropriate, and maintaining the required equipment; 3. Histology/lmmunohistochemistry Service: This component will process cells and tissues provided by investigators for histologic and immunhistochemical evaluation. Functions will include tissue embedding and sectioning, histochemical and immunohistochemical staining of cells and tissues, equipment maintainance and assistance in the data interpretation. Core C will now also produce, test, and standardize inactivated Ft (iFO-mAb complexes, which will be used by all 3 subprojects.